When adjusting records for environmental effects, which two factor models are commonly used?

• A. Additive factors and Multiplicative factors
• B. Linear and Non-linear
• C. Categorical and Continuous
• D. Fixed and Random

Answer: (A)

When adjusting records for environmental effects, you want a model that separates the overall differences due to environments and genotypes from the way those two factors interact. The additive main effects and multiplicative interaction approach does exactly that: the additive part handles the main effects of genotypes and environments, while the multiplicative part captures the interaction structure between them. This lets you explain most of the variation with a few multiplicative terms, making it easier to adjust records and compare genotypes across different environments. The other options don’t specifically describe this two-part decomposition: linear vs nonlinear is about the shape of the relationship, categorical vs continuous is about data type, and fixed vs random is about how effects are treated in a model, not the particular two-factor decomposition used to adjust for environmental effects.